Field of the Invention
The present invention relates to an encoder and a scale used for the encoder.
Description of the Related Art
Japanese Patent No. 2011-237231 discloses an encoder that is provided with a displacement detection sensor to detect a displacement in a lateral direction orthogonal to a measuring direction (a moving direction) to be able to display a displacement between a scale and a detector. In this configuration, the detector and the scale can be adjusted and fixed to have a predetermined position relation, and therefore appropriate signal characteristics can be obtained.
However, in the encoder disclosed in Japanese Patent Laid-Open No. 2011-237231, the displacement detection sensor, a peripheral circuit to connect an output signal obtained from the displacement detection sensor to a microcomputer (a signal processing circuit), and the like are necessary. Therefore, it is a factor of increasing the size and the cost of the encoder. In addition, a scale region to detect a direction (the lateral direction) perpendicular to the measuring direction (the moving direction) and a scale region to detect the measuring direction are arranged separately from each other. Therefore, due to a position variation such as yawing, a displacement is generated between them and an accuracy of detecting the position is deteriorated.